DESCRIPTION: Human herpes virus 8, (HHV-8) has been identified in Kaposis sarcoma (KS) as well as in a variety of other tissues including those from the oral cavity. This proposal seeks to determine 1) the cell types in the oral mucosa that support HHV-8 infection, 2) the dependency of cellular differentiation on viral replication, 3) the association of oral HHV-8 infection with oral KS and oral ulceration, 4) the role of HIV-1 co-infection in enhancement of HHV-8 activity and 5) evaluate saliva as a vehicle of HHV-8 transmission. In-situ hybridization and in-situ PCR techniques will be used to identify the cells harboring HHV-8 and HIV-1 genomes and in the cultures of differentiating epithelial cells. A limited cohort and study will be done on HIV-1 positive patients to determine parameters associated with the development of oral KS.